Monday, 9 March 2020

Estuary at sunset, Mersehead RSPB reserve

The RSPB's Work on Toads, Bumblebees and Beetles

We seem to have been very lucky this session in having speakers of a very high calibre and tonight's speaker was no exception. James Silvey is the RSPB Scotland's Species and Habitats Officer, and has been tasked with looking after the the non-avian species that inhabit the Scottish reserves. The RSPB has drawn up an all nature plan highlighting 23 species throughout the UK that require conservation. Of the 15 of these species that occur in Scotland and 12 occur on RSPB reserves. For his talk James chose three of these species, the great yellow bumblebee, the short-necked oil beetle and the natterjack toad, to illustrate the work being carried out.

Because of the loss of hay meadows and changes in farm practices over the past 100 years, the distribution of the great yellow bumblebee has changed from being found all over the British Isles to being restricted to the Western Isles, Coll and Tiree, the north coast of mainland Scotland, and the Orkney Isles. The RSPB has concentrated on the bumblebees in its Orkney reserves, managing the reserves for them. By planting their favoured plants of birds-foot trefoil, red clover, vetches and knapweed, and providing suitable habitat for nest sites and the overwintering of queens, the Society is hoping to maintain and increase the bumblebee numbers on its reserves on Orkney mainland and the islands of Shapinsay and Copinsay.

The short-necked oil beetle is a small, flightless, black beetle with a large abdomen. These insects were thought to be extinct in the UK until some were found in South Devon in 2007 and on the RSPB reserve on the island of Coll in 2010. The insects get their name from the poisonous secretion they emit when alarmed which looks like oil. This substance causes blistering and gives the more general name of blister beetles to this family of insects. This liquid is passed to the female during mating and is used to cover and protect the eggs. The tiny beetle larvae parasitise solitary bees by leaping onto a bee's back from a hiding place within a flower head. The bee takes the larva back to its nest where it eats the bee's provisions and its undeveloped young. A survey on Coll in 2014 found over 150 beetles on the reserve's coastal sand dunes.

Natterjack toads are the scarcest of all British toad species. They occur in sand dunes and sandy areas along the Solway, Cumbrian and Merseyside coasts and locally on the Lincolnshire and East Anglian coastlines. They used to frequent southern English heathlands and reintroduction programmes are underway to recolonise some of these areas. The RSPB reserve at Mersehead has been a haven for these rare animals for some years. The need to move a population of toads from a development area at nearby Southerness and the acquisition of a plot of coastal land gave more impetus to the reserve to manage land for these amphibians. The toads breed in fresh water pools that dry up during the summer. In 2014 a major storm adversely affected the sand dunes, caused salination of the fresh water pools and led to the introduction of a new survey method. Rather than counting spawn strings, male toads were found by following their croaking song and were individually identified by the markings on their backs. The survey conducted on three nights a year for three years proved there were about 150 adult toads on the reserve, three times more than had been previously thought.

This fascinating and informative talk by James on the conservation of non-avian species on RSPB reserves was followed by a question and answer session and a hearty vote of thanks.